1. Field of the Invention
The present invention relates to a polymer optical waveguide module which is equipped with an emitter or detector, and an optical waveguide.
2. Description of the Related Arts
As a method for manufacturing a polymer optical waveguide, proposed are (1) a method of dipping a film in a monomer, selectively exposing a core portion to change its refractive index and adhering the film (selective polymerization method), (2) a method of forming a core layer and a clad layer by applying coating of core and clad materials and then forming a clad portion by reaction ion etching (RIE method), (3) a method of using photolithography by carrying out exposure and development using a UV curable resin obtained by adding a photosensitive material to a polymer material (direct exposure method), (4) a method of using injection molding; and (5) a method of forming a core layer and a clad layer by applying coating of core and clad materials, and exposing a core portion to change its refractive index (photobleaching method).
In recent IC or LSI technology, in order to improve operation speed or integration degree, optical interconnections between devices, between boards in the device or in the chip have drawn attentions instead of high-density electrical interconnections.
As a device for optical interconnections, described in Japanese Published Unexamined Patent Application No. 2000-39530 is an optical device including an emitter and a detector in a stacking direction of a core and a clad of a polymer optical waveguide in which the core has been encompassed by the clad, and further including an input-side mirror for inputting light from the emitter into the core and an output-side mirror for outputting the light from the core into the detector, wherein at positions corresponding to an optical path extending from the emitter to the input-side mirror, and an optical path extending from the output-side mirror to the detector, the clad layer is recessed to converge the light from the emitter and light from the output-side mirror. In Japanese Published Unexamined Patent Application No. 2000-39531, described is an optical element for inputting light from an emitter to the core end face of a polymer optical waveguide having a core and a clad encompassing the core, wherein the light input end face of the core is protruded toward the emitter to converge the light therefrom, whereby a waveguide loss is suppressed.
In Japanese Published Unexamined Patent Application No. 2000-235127, described is an optoelectronic integrated circuit having a polymer optical waveguide circuit fabricated directly over an optoelectronic combined circuit substrate in which an electronic device and an optical device are integrated.
In the above-described optical interconnection, if the devices as described above can be mounted and incorporated in an apparatus, fabrication of optical interconnections can be designed more freely, and as a result, an emitter or detector which is small and compacted can be obtained.
In the methods so far proposed, however, a mirror must be embedded in order to form a 90° folded mirror or an optical waveguide and an emitter or a detector must be aligned with high precision upon their adhesion. The cost necessary for mounting has been a serious problem.